Propellant tanks are pressure vessels configured to store pressurant, such as liquid fuel, liquid oxidizer, or other chemical substances used to propel a vehicle. For example, rockets and aircrafts may rely upon stored pressurant to generate propulsive thrust to enable flight. Efficient use of pressurant is important for various reasons, including the cost and weight associated with the pressurant. Therefore, measures are often taken to improve pressurant expulsion efficiency.
One measure aimed to improve pressurant delivery involves using a tank pressurization diffuser that can reduce undesirable mixing of tank ullage gas or vapor with the liquid pressurant in a tank. In particular, a diffuser can be configured to passively introduce a pressurizing gas or vapor (also simply referred to as pressurant) directly into the upper region of a liquid propellant tank in such a manner as to reduce the velocity of the vapor or gas to prevent inadvertent mixing with the liquid pressurant already stored within the tank. The diffuser can be designed with the goal of limiting or eliminating direct impingement of the pressurant with the liquid propellant to decrease the heat transfer between the pressurant and liquid surface to ensure optimum expulsion and pressurization efficiency.
Existing diffusers are historically assembled from multiple components, such as screens or perforated components including machined parts that are attached together via mechanical fasteners (e.g., screws, bolts, and rivets) or by brazing or welding. The multiple component configuration of the diffuser, however, can result in vibrational, fatigue, and other operational problems that could impact performance. The multiple-component configuration also requires individually manufacturing each component prior to assembly which consumes additional touch labor time and adds additional expense. Furthermore, since the parts must be assembled together using simple shapes (flat surfaces for example), the complexity of the diffuser's design is often limited by traditional manufacturing processes, which can then limit the capabilities and performance of the diffuser. Thus, there is a need for a non-conventional diffuser design and manufacturing process that is capable of receiving and passively (in traditional use) redirecting pressurant in a manner that effectively reduces unwanted mixing of pressurant within a tank while also avoiding the limitations of traditional, multiple-component diffusers.